Light front end / tank slappers at 85+mph (136kmph) after new tires?

[ducaticowboy]

Hey folks,

Got new Dunlop Trailmax tires recently (80 miles on them so far) and noticed that as soon as I hit 85+mph, the front end gets light and goes into a wobble / tank slapper. This is regardless of the road. 

 

If I sit on the passenger seat at the same speed and take weight off the front, it doesn’t happen (or it’s about 90% less intense). 

 

They balanced the tires at the shop, and I’m getting mixed messages from different mechanics saying it could be balance while others say balance issues typically happen at 60mph or wouldn’t cause that at 85mph.

 

Another mechanic told me to check the fork neck bearings but as this is a brand new bike, that doesn’t make much sense. Yet another mechanic said to check alignment. 
 

I’ve lowered the tire pressure, same issue. Besides a defective tire, the only other thing I can think of is that I also installed the extended puig touring windscreen - do you think a taller windscreen can cause wobble on the front? I have inspected the front tire while it is rolling and I can’t see any wobbling from it.

 

Other than that, is there anything else I should be looking at, like a suspension adjustment on the front for rebound or compression?

 

One very experienced friend said to put in a bottle of ride-on self balancing tire sealant, yet others have told me this is a bad idea. 

 

I’ve talked to several mechanics and none of them are in agreement with what to try + they are all booked for weeks. Is it possible that a balance issue only appears at that speed?

 

Any tips on how to investigate this are greatly appreciated.

[advrallymoto]

There are much more knowledgable people than I when it comes to suspension and tires and whatnot but I'll give you my thoughts.  If I'm way off someone feel free to correct me.

 

My understanding is that tires, road debris, etc may start a wobble in the front, but it won't persist and turn into a tank slapper if your suspension is set up correctly.  The first thing you need to do is set your preload in the front and rear for your specific weight.  That may take care of it all together, but it doesn't sound like those tires are helping much.  

 

Is the trailmax a directional tire?  Is it installed backwards maybe?  Like I said, my limited understanding is that a tire cant *cause* a tank slapper, it can only cause the wobble.  The conditions for the tank slapper already existed between how the bike suspension is set and your weight and where your weight is biased on the bike.

 

 

[Hibobb]

As I am being Chatty Cathy today, I will add my two-cents

 

1) Take your new touring windscreen off and see what happens.

2) Tires may be balanced, but is the bead seated correctly?

Lift the front end with a jack and spin the tire while you have something stationary next to the tire to be a visual gauge. Check for up/down variance... Also side/side (as in a bent rim).

3) Tapered steering head bearings didn't wear out yet, but it is an easy thing to check adjustment (good time to add grease if they look dry).

 

Best of luck...

[AZJW]

@ducaticowboy Agreed, setup your suspension first. I had previously setup my suspension including replacing the oem with a 90nm rear spring and sag is now perfect with only a click or two of pre-load. After that, I replaced my oem Pirellis with a MotoZ RallZ  that induced wobbling, not a tank slapper, but felt like it could develop into one.  I went with a MotoZ RallZ front tire that many here swear by, but it just didn't work for me.  I switched out to my front for the Dunlop Trailmax Mission and it cured my front end wobbling issues.  If, after setting up your suspension,  checking all fasteners for proper torque and  assuring your forks are aligned, my money would be spent on replacing that front tire. Good luck!

[ducaticowboy]

4 minutes ago, Hibobb said:

As I am being Chatty Cathy today, I will add my two-cents

 

1) Take your new touring windscreen off and see what happens.

2) Tires may be balanced, but is the bead seated correctly?

Lift the front end with a jack and spin the tire while you have something stationary next to the tire to be a visual gauge. Check for up/down variance... Also side/side (as in a bent rim).

3) Tapered steering head bearings didn't wear out yet, but it is an easy thing to check adjustment (good time to add grease if they look dry).

 

Best of luck...

One thing I do notice is that while it’s on the lift And I spend the front tire, it’s not completely free, there is a tiny little bit of brake pad contact. The contact is not even throughout the spin. I’m no tire or suspension expert, but is there away the front could be slightly misaligned and the brake pad slightly touching is a symptom? 

[AZJW]

Might check this out also.

 

 

[DavidS]

Start with the inexpensive stuff first, check to see the tires are ok, and they are balanced. Sometimes the weights come off and that can create weird behavior in the tires at speed. If you have the option, put another front wheel (a buddy's if possible) on and see if it continues. If it disappears, you can narrow it down to the tire or rim.

 

I would go back to the place where you had the tires installed and have them check them it out. They should have the tools to identify the issue, and help you get it resolved quickly.  

[REDHORSECA]

Did you install lowering links?

If so did you adjust the fork heights  on the triple clamps (~50% by how much the links lowered the rear)?

[loneranger700]

Mine has actually started to do this. Not that bad, but it only started after doing some heavy off-road work. Methinks the front wheel spokes might be out of true.

[Louis]

You just replaced the tyres and you noticed this wobbly behaviour, right ? Assuming nothing else has changed (like additional luggage), common sense says, it must be the tyres. Perhaps the rims/wheels were damaged during installation, or the wheels are out of alignment post tyre installation.

Plenty of fellow forum inmates had this problem with the stock tyres, a few had issues with their wheels. 

[papab]

I would do some testing without the new windscreen

[UtahJack]

@ducaticowboy

I also have the Trailmax tires, about 1000 mi. so far love the tires, much improved over stock ones on and off road.

That being said I have noticed a little head shake at speeds over 95mph. but very minor and only when putting hard input to make a pass. Nothing close to a tank slapper just feels like she is real light and would benefit from a steering dampener, I am still investigating not happy with how much weight it took to balance these tires but I was thinking that may be due to the heavy duty tubes I put in.  I have not noticed any problem when carving tarmac canyons at high speeds.

As far as what you were told about balancing, out of balance issues are speed related what speed that is will vary depending upon many factors, they can show up at any speed, but will be consistent with that speed as far as not happening below or above.

If you are sure the tire is balanced properly, check that it is trued.

If the above checks out, you might want to string the bike and check the alignment. Put the bike on the center stand or tie it down so it is straight up, check that the rear sprocket is riding centered in the chain, with some help run a string so it is just touching the rear tire at two points front and rear, run the string past you front wheel with the steering straight check that you have a equal gap at two points on the front tire. You can also use something like one of Stanley's laser levels instead of the string makes it a little easier. 

If it come out wrong check your front forks first, make sure they are equal distances on the upper triple tree, than loosen the bolts on the lower triple tree and the front axle clamp and then plunge the front suspension several times, tighten the axle first than the lower triple tree to requires torque and recheck everything. 

Hopefully this will help.

Edited June 7, 2021 by UtahJack

[Goldentaco]

On 6/6/2021 at 9:53 AM, ducaticowboy said:

Hey folks,

Got new Dunlop Trailmax tires recently (80 miles on them so far) and noticed that as soon as I hit 85+mph, the front end gets light and goes into a wobble / tank slapper. This is regardless of the road. 

 

If I sit on the passenger seat at the same speed and take weight off the front, it doesn’t happen (or it’s about 90% less intense). 

 

They balanced the tires at the shop, and I’m getting mixed messages from different mechanics saying it could be balance while others say balance issues typically happen at 60mph or wouldn’t cause that at 85mph.

 

Another mechanic told me to check the fork neck bearings but as this is a brand new bike, that doesn’t make much sense. Yet another mechanic said to check alignment. 
 

I’ve lowered the tire pressure, same issue. Besides a defective tire, the only other thing I can think of is that I also installed the extended puig touring windscreen - do you think a taller windscreen can cause wobble on the front? I have inspected the front tire while it is rolling and I can’t see any wobbling from it.

 

Other than that, is there anything else I should be looking at, like a suspension adjustment on the front for rebound or compression?

 

One very experienced friend said to put in a bottle of ride-on self balancing tire sealant, yet others have told me this is a bad idea. 

 

I’ve talked to several mechanics and none of them are in agreement with what to try + they are all booked for weeks. Is it possible that a balance issue only appears at that speed?

 

Any tips on how to investigate this are greatly appreciated.

I've encountered this issue with Motoz tires and the issue seems fairly straight forward but looks in line with the Dunlops.

 

Our Stock front rim is 1.85"  Most Adventure bikes run a 2.5 or 2.15 rim size so MFG's build the tire to that spec.  Offroad bikes often run narrower rims for more strength and better grip.  Yamaha looks to have bridged the gap so at times you will see this issue with a tire built for a wider rim being squeezed onto a narrower rim.  It reduces the contact patch and makes the tire profile more sharp.  Think of a baseball hat brim that you flatten or make more round.

 

From Dunlop's site: Notice the front rim size 2.15x21

 

Now check the tire specs:

 

While these are not knobby tires, the issue remains unresolved unless you move to the correct size rim.  Sure the difference "seems" minimal and yes the tire does "fit" but you are experiencing what happens when the contact patch is not contacting the road as designed.

 

Why does Dunlop say they fit?  Technically they do and I'll just say you shouldn't be riding 85mph anyway...I' know whatever.

 

I bet if you lowered the pressure, it might help...might not help longevity but with fit incompatibility there's always tradeoffs.

 

When looking at tire reviews be sure you're comparing apples to apples.  Check for reviews of tires on bikes with similar sized rims and if possible similar weights.  If weight isn't the same the rim size will be what you want to look for for handling issues.  Not all tires will behave badly when installed outside their design parameters.

 

For point of reference it may be worth noting for when you read tire reviews:

All 21" Front rims

Tenere 700= 1.85" rim width

DR650 = 1.85" rim width

KLR650 - 1.65 rim width

Husqvarna 701=1.85 rim width

Africa Twin=2.15" rim width

KTM 790= 2.50 rim width

BMWF850 GS= 2.15" rim width

DRZ 400 = 2.15" rim width

 

J

 

Edited June 11, 2021 by Goldentaco

[loneranger700]

Kind of strange addition to this, but if any of you guys have this problem, I've discovered it actually goes away when I do two up. The strangest thing. And I'm running motoz rear and anakee fronts.

[rumrum]

9 hours ago, Goldentaco said:

I've encountered this issue with Motoz tires and the issue seems fairly straight forward but looks in line with the Dunlops.

 

Our Stock front rim is 1.85"  Most Adventure bikes run a 2.5 or 2.15 rim size so MFG's build the tire to that spec.  Offroad bikes often run narrower rims for more strength and better grip.  Yamaha looks to have bridged the gap so at times you will see this issue with a tire built for a wider rim being squeezed onto a narrower rim.  It reduces the contact patch and makes the tire profile more sharp.  Think of a baseball hat brim that you flatten or make more round.

 

From Dunlop's site: Notice the front rim size 2.15x21

 

Now check the tire specs:

 

While these are not knobby tires, the issue remains unresolved unless you move to the correct size rim.  Sure the difference "seems" minimal and yes the tire does "fit" but you are experiencing what happens when the contact patch is not contacting the road as designed.

 

Why does Dunlop say they fit?  Technically they do and I'll just say you shouldn't be riding 85mph anyway...I' know whatever.

 

I bet if you lowered the pressure, it might help...might not help longevity but with fit incompatibility there's always tradeoffs.

 

When looking at tire reviews be sure you're comparing apples to apples.  Check for reviews of tires on bikes with similar sized rims and if possible similar weights.  If weight isn't the same the rim size will be what you want to look for for handling issues.  Not all tires will behave badly when installed outside their design parameters.

 

For point of reference it may be worth noting for when you read tire reviews:

All 21" Front rims

Tenere 700= 1.85" rim width

DR650 = 1.85" rim width

KLR650 - 1.65 rim width

Husqvarna 701=1.85 rim width

Africa Twin=2.15" rim width

KTM 790= 2.50 rim width

BMWF850 GS= 2.15" rim width

DRZ 400 = 2.15" rim width

 

J

 

I did not even think about this when purchasing my front tyres. I'm running Motoz Rallz tubless on the front and have been very disappointed with the on road handling. I just Checked the specs on the Motoz site and they quote minimum permissible size rim for the 90/90 tubeless is 2.15". This would explain allot, as the only way I can get a satisfactory handling is to run at a lower pressure at around 26 psi.  Cheers for the enlightenment. Time to go tyre shopping again.

[Goldentaco]

12 minutes ago, rumrum said:

I did not even think about this when purchasing my front tyres. I'm running Motoz Rallz tubless on the front and have been very disappointed with the on road handling. I just Checked the specs on the Motoz site and they quote minimum permissible size rim for the 90/90 tubeless is 2.15". This would explain allot, as the only way I can get a satisfactory handling is to run at a lower pressure at around 26 psi.  Cheers for the enlightenment. Time to go tyre shopping again.

No need to go tire shopping.  I had the same thing happen with a set of Desert H/T TL.  I have since switched to the Rallz Tube Type ( TT) and they have been awesome.  The bad handling is what got me on the trail of the whole rim width rabbit hole.

 

My experience in this thread:

 

with update after swapping to the TT Rallz.

 

 

J

[rumrum]

2 hours ago, Goldentaco said:

No need to go tire shopping.  I had the same thing happen with a set of Desert H/T TL.  I have since switched to the Rallz Tube Type ( TT) and they have been awesome.  The bad handling is what got me on the trail of the whole rim width rabbit hole.

 

My experience in this thread:

 

with update after swapping to the TT Rallz.

 

 

J

Just looking back on the Motoz site, looks like the tube type as you stated are suitable for the 1.85" rim unlike the tubeless. The tyres are nice off road but shite on it so think I will ditch the tubeless ones in favour of the tubed type as you have.

[AZJW]

@rumrum Be advised my experience was different with the tubed 90/90-21 MotoZ RallZ. It exhibited the aforementioned pavement stability issues, but did excel off-road.  I really wanted to like that front tire trying different pressures, more miles, etc.,  but it was an exercise in futility.   I swapped the RallZ front out for the same size Dunlop Trailmax Mission and am very happy with that tire combined with a RallZ 150/80-18 rear. The DTM isn't quite as good in the sand as the RallZ, but all other aspects of that tire are great and will probably be my go to front for the T7. Ymmv.

[Jarrid]

Was searching around the web and this was basically the thread I was looking for to help with my same issue. I put on the Mitas EO9 with a Dunlop 606 front. The off road was ok with the right tire pressure but on road, above 135Kmh the bike would start to lightly shake back and forth. Not quite a full tank slapper but felt like it would have gotten there if I kept going up in speed. Went to an EO9 front thinking it was the 606 but it still happens. Long story short is same thing as stated here. If I sit back on the passenger seat or have a passenger the shake goes away and the bike is stable. I went to a heavy rear spring a couple weeks ago and thinking that now with that combined with the rear tire being different, possibly taller, has made too steep of a head angle. Might need to put stiffer front springs in or look into dropping the forks further down the triple clamp. 

[Landshark]

7 hours ago, Jarrid said:

Was searching around the web and this was basically the thread I was looking for to help with my same issue. I put on the Mitas EO9 with a Dunlop 606 front. The off road was ok with the right tire pressure but on road, above 135Kmh the bike would start to lightly shake back and forth. Not quite a full tank slapper but felt like it would have gotten there if I kept going up in speed. Went to an EO9 front thinking it was the 606 but it still happens. Long story short is same thing as stated here. If I sit back on the passenger seat or have a passenger the shake goes away and the bike is stable. I went to a heavy rear spring a couple weeks ago and thinking that now with that combined with the rear tire being different, possibly taller, has made too steep of a head angle. Might need to put stiffer front springs in or look into dropping the forks further down the triple clamp. 

 

This is interesting.  I would like to know what your findings are.  Have you checked the rim for run out?  Is the front tire balanced? Although that would be a different symptom, still nice to know.  Any noticeable defects in the tire?  And have you set up the sag correctly for your weight with gear considering a new spring was installed?  

Thanks for your answers.

[Jarrid]

On 7/26/2021 at 5:26 AM, Landshark said:

 

This is interesting.  I would like to know what your findings are.  Have you checked the rim for run out?  Is the front tire balanced? Although that would be a different symptom, still nice to know.  Any noticeable defects in the tire?  And have you set up the sag correctly for your weight with gear considering a new spring was installed?  

Thanks for your answers.

I have been doing some testing but still have not nailed down the problem.  Front Sag is 37mm static and 64mm race. Rear sag is 43mm static and 80mm race. Spring preload on back is backed right off. I took the front tire off again and had it static balanced and it is good. I have been playing with the fork height and can get the tank slap to go way if I ride on the back seat or drop the forks below flush of the triple clamps but that might just be away of masking the problem and taking away handling in other areas.  That all being said the EO9 is taller on the bike and the centre of the axle sits a half

inch higher then stock. and that may be contributing to the issue.  Maybe these EO 9s are no good for highway speeds. Might swap the front back to stock tonight to see what happens. 

[vicep3]

I also just installed a pair of Dunlop Trailmax Mission tires. Between 50-70kph it feels like the front tire hops - like one of those clown tires. The wheel was balanced after tire installed plus spoke tension/truing done at the same time. Above 70kph the feeling goes away. Riding around town it feels like the pavement is a wave. Interesting the comment above regarding rim width.

Bought these to replace Bridgestone Battlax AX41 as I thought I would get better tire mileage. The Dunlops sure don't give the same confidence on gravel or dirt even though they are supposed to be 50/50. I think I'll be switching back long before these are done.

[Landshark]

10 hours ago, vicep3 said:

I also just installed a pair of Dunlop Trailmax Mission tires. Between 50-70kph it feels like the front tire hops - like one of those clown tires. The wheel was balanced after tire installed plus spoke tension/truing done at the same time. Above 70kph the feeling goes away. Riding around town it feels like the pavement is a wave. Interesting the comment above regarding rim width.

Bought these to replace Bridgestone Battlax AX41 as I thought I would get better tire mileage. The Dunlops sure don't give the same confidence on gravel or dirt even though they are supposed to be 50/50. I think I'll be switching back long before these are done.

 

That sure seems like a tire out of balance.  I'd check that for yourself just for peace of mind.  If you were to change out the tire it would probably go away I'm guessing.  Next to that, maybe a defective tire.

[Jarrid]

Has anyone had any breakthrough revelations on the light tank slapper situation? My next step is to go back to the stock tires, one at a time. 

[williestreet]

Fix your sag.  

Front and rear should be 60mm rider sag.  Crank up the rear preload to get proper sag.  When you lift the rear it will weight the front and probably bring it back down to pretty close to proper 60mm.

 

Riding the bike like a chopper is a sure way to get wobble/headshake.

 

I wouldn't be blaming/changing tires until I get the geometry correct.

[Jarrid]

4 minutes ago, williestreet said:

Fix your sag.  

Front and rear should be 60mm rider sag.  Crank up the rear preload to get proper sag.  When you lift the rear it will weight the front and probably bring it back down to pretty close to proper 60mm.

 

Riding the bike like a chopper is a sure way to get wobble/headshake.

 

I wouldn't be blaming/changing tires until I get the geometry correct.

Sag is perfect with about 15 Clicks in.  No difference at 60mm sag or 80mm sag, bars still slap. This is the rear spring I am running. It is this Race tech one highlighted below.  It doesn't slap if I sit on the passenger seat or have a passenger on it.